Electrical push button switch with improved slider contact



Feb. 27, 1968 E. MILNER ELECTRICAL H BUTTON SWITCH WITH SLI IMPRO CONTACT Filed Feb. 1967 7 l 4; 4 3' 4 7 FKlb.

' FIG. 5.

FIG.8.

ILL/ I fl /Y 7 A 8 FIG. IO

United States Patent ()fiice 3,371,168 ELECTRICAL PUSH BUTTON SWITCH WITH IMPROVED SLIDER CONTACT Ernest Milner, Cynroed, Cardiff, Wales, assignor to A. B. Metal Products Limited, Glamorgan, Wales, a British company Filed Feb. 28, 1967, Ser. No. 619,439 Claims priority, application Great Britain, Jan. 10, 1967, 1,391/ 67 7 Claims. (Cl. 200-16) ABSTRACT OF THE DISCLOSURE A push-button switch of the type including a housing for spaced fixed contacts and a slider carrying moving contacts arranged to bridge selected pairs of fixed contacts. The moving contacts are arranged in recesses in the slider and having a long arm for bridging the fixed contacts and one or two short arms connected to the long arm and resting by this free end on the inner surface of the recess, so as to support the long arm for rocking movement during changeover.

This invention relates to electrical switches, and more particularly to contact arrangements for push-button switches.

Push-button switches may include a stator or housing supporting fixed contacts, e.g. round wires passing through the housing and having protruding end portions acting as terminals for connection to leads or printed circuits. In one particular form of push-button switch, a selector or slider in the housing is directly actuated by the push-button mechanism and supports movable contact elements adapted to bridge and connected adjacent fixed contacts in the housing, and in particular to connect a selected fixed contact to its neighbouring contacts in dependence on the position of the push-button mechanism.

In one such construction a boss has been provided in a recess in the slider to act as a pivot point of the movable contacts to enable it to rock during a changeover. This leads to great precision being required in the manufacture of the parts and to difficulties in assembly.

According to the invention, a puslnbutton switch incorporates a slider having one or more recesses mounting the movable contacts which are in the form of leaf springs having a long arm adapted to bridge fixed contacts and a short arm adjacent the inner wall of the recess, one end of the said long arm and the short aim being linked by a return bend and the short arm having its free end adapted to act as a pivot point for rocking movement of the movable contact during a changeover.

The free end may be turned over and/ or may rest on the plane inner surface of the recess or it may be turned over and rest in a secondary recess formed therein.

This leads to simplification of the manufacture and assembly.

In a preferred form the movable contacts may have a second short arm connected to the other end of the long arm by a return bend.

The invention will be further described with reference to the accompanying drawings, in which:

FIGURES l to are sectional views of various forms of the invention;

FIGURE 6 is a side elevation of the contact of FIG- URE 5 in free position;

FIGURE 7 is an end elevation of the contact of FIG- URE 6;

FIGURE 8 is a plan view of the contact of FIGURES 6 and 7;

FIGURE 9 is a plan view of a blank from which the contact of FIGURES 6 to 8 may be formed; and

3,371,168 Patented Feb. 27, 1968 FIGURE 10 shows an alternative form of blank.

Each of the FIGURES 1 to 4 shows part of one wall 1 of a housing and part of a slider or selector 2. Fixed contacts in the form of round wires 3, are mounted in the wall 1 and cooperate with movable contacts 4 mounted in recesses 5 in the slider 2. Each movable contact has a long arm 4a, and a short arm 4b linked by a U-bend 4c, and the free end of the short arm 4b is turned over as at id to provide a pivot point for rocking action of the movable contact during a changeover.

In FIGURE 1 the end 4d rests in a secondary recess formed in the inner surface of the recess 5, which is plane in this case.

In FIGURE 2 the inner surface of the recess is formed by two inclined planes, and the secondary recess extends as far as the full depth of the recess 5.

In FIGURE 3 the secondary recess is shown as being of conical shape rather than of square section.

In FIGURE 4 the secondary recess has been dispensed with completely and the free end 4d rests on the flat inner surface of the recess 5.

FIGURE 5 shows two opposed walls 1 on the housing, each wall having fixed contacts in the form of round Wires 3 set therein for co-op-eration with movable contacts 4 set in opposed recesses in the slider 2. The recesses are of a form having plane bases, and the contacts 4 each comprise a long arm 4a and a pair of similar short arms 4e linked to opposite ends of the arm 4a by U-bends 4c. In this case the short arms are of substantially the same length as the long arms and of a reduced width so that they can cross each other as illustrated.

This is more clearly illustrated in FIGURES 6 to 8 which show the contact of FIGURE 5 in a free position. It is also seen from these figures that the contact is formed with a longitudinal stiffening rib 6 on the long arm 4a, which rib 6 has end expansions 6a adjacent the ends of the long arm 4a.

FIGURE 9 shows a blank from which the contacts of FIGURES 6 to 8 can be formed. It is seen to comprise a main body portion 8 which is destined to form the long arm 4a and the U-bends 4c, and reduced width end por tions 9 which form the arms 4e.

FIGURE 10 shows a modified form of blank wherein the end portions 9a are tapered instead of being of a uniform width. It is clear that with either form of blank the width of the end portion 9 or 9a in the zone where the arms 4b are destined to cross must not be greater than half of the final width of the arm 44:.

Various modifications may be made within the scope of the invention.

I claim:

1. A push-button switch comprising a housing, spaced fixed contacts mounted in the housing, a slider supported in the housing for reciprocating movement, said slider having at least one recess having an inner wall, a movable contact in the form of a leaf spring in the recess, the leaf spring having a long arm adapted to bridge adjacent fixed contacts, a short arm adjacent the inner wall of the recess, and a return bend linking the long and short arms; the switch having the improvement that the short arm has its free end adapted to act as a pivot point for rocking movement of the movable contact on the inner wall of the recess during a changeover caused by movement of the slider.

2. A push-button switch as claimed in claim 1, in which the free end of the short arm is turned over.

3. A push-button switch as claimed in claim 2, in which the inner surface of the recess is plane.

4. A push-button switch as claimed in claim 2, in which the inner surface of the recess includes a secondary recess, and the turned over free end of the short arm rests in the secondary recess.

(i t 5. A push-button switch as claimed in claim 1, in which the short arms taper in Width away from the return each movable contact includes a second short arm and a bends. Y 7 second return bend connecting the second short arm to References Cited the long arm, the free end of the second short arm rest- FOREIGN PATENTS ing on the inner surface of the recess. 5

1,054,914 1/1967 Great Britain.

6. A push-button switch as claimed in claim 5, in which the short arms are narrower than the long arm and are arranged to cross each other between t e long arm and ROBERT K. SCHAEFER, a y Examiner.

the inner surface of the recess.

7. A push-button switch as claimed in claim 6, in which 10 J. R. SCOTT, Assistant Examiner.

1,054,915 1/1967 Great Britain. 

